[S] Change in coreboot[main]: acpigen_ps2_keybd: Add Fn key to linux,keymap

[Felix Held (Code Review)]

Felix Held has submitted this change. ( https://review.coreboot.org/c/coreboot/+/81895?usp=email )

Change subject: acpigen_ps2_keybd: Add Fn key to linux,keymap
......................................................................

acpigen_ps2_keybd: Add Fn key to linux,keymap

Some devices may generate scancodes for the Fn key if they have one.
If they do, we should add them to the linux,keymap binding.

BUG=b:333096023
TEST=Flash DUT that emits a scancode for the Fn key, verify that it is
mapped to KEY_FN in the Linux kernel using `evtest` when pressing the Fn
key.

Change-Id: Ie4daa64bc6b619392276d0b5f16e2d195d5bd68c
Signed-off-by: Aseda Aboagye 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81895
Tested-by: build bot (Jenkins) 
Reviewed-by: Shelley Chen 
---
M src/acpi/Kconfig
M src/acpi/acpigen_ps2_keybd.c
2 files changed, 15 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Shelley Chen: Looks good to me, approved

diff --git a/src/acpi/Kconfig b/src/acpi/Kconfig
index 417ff60..2bb56ba 100644
--- a/src/acpi/Kconfig
+++ b/src/acpi/Kconfig
@@ -14,6 +14,14 @@
      Specifies the ACPI name format string used by the acpigen
      function to generate the processor scope. Default is CPxx.

+config ACPI_FNKEY_GEN_SCANCODE
+	int
+	default 0
+	help
+	  Specifies the scancode, if any, which is generated when the Fn key is
+	  pressed. A value of 0 is ignored, which is the default since most
+	  keyboards do not emit a scancode for the Fn key.
+
 config ACPI_HAVE_PCAT_8259
    def_bool y if !ACPI_NO_PCAT_8259

diff --git a/src/acpi/acpigen_ps2_keybd.c b/src/acpi/acpigen_ps2_keybd.c
index 6590e66..cc21d5d 100644
--- a/src/acpi/acpigen_ps2_keybd.c
+++ b/src/acpi/acpigen_ps2_keybd.c
@@ -244,6 +244,13 @@
    		acpi_dp_add_integer(dp_array, NULL, keymap);
    	}

+		/* Add the Fn-key */
+		if (CONFIG_ACPI_FNKEY_GEN_SCANCODE != 0) {
+			acpi_dp_add_integer(dp_array, NULL, KEYMAP(CONFIG_ACPI_FNKEY_GEN_SCANCODE,
+								   KEY_FN));
+			total++;
+		}
+
    	total += num_top_row_keys;
    }